Vitrifying refractory composition and product



Dec. 19, 1950 H. L. WHlTMAN 2,534,327

VITRIFYING REFRACTORY COMPOSITION AND PRODUCT Filed Sept. 6, 1946 Patented Dec. 19, 1950 VITRIFYING REFRACTORY COMPOSITION AND PRODUCT Henry L. Whitrnan, Los Angeles, Calif., assignor, by decree of court, to Katherine L. Whitman Application September s, 1946, Serial No. 695321 '7 Claims. (CI.- 106-49) First,'to provide an improved vitrifyirig com position adapted to be readily applied as 'afcoating to furnace and fire box bricks and to crucibles 'of graphite, fire clay and silicon carbide' and to other objects of refractory material, and when so-'applied adapted to be converted b at into a vitrified refractory coating, which is `cry hard and resistant to very high temperatures. Second, to provide a composition ofth`e above type which contains silicate ingredient in excess of basic or neutral ingredients andi which is 'adapted to be converted by heat into-ja vitrifled refractory, semi-glazed acid-type coating for refractory materials, which resists heatj and the destructive action of flames, gases and-acids and which protects the walls to which it is applied against spauling, cracking and meltingto thereby` greatly prolong the life of such walls.

Third, to provide a composition of--the above type which may be economically applied as a coating, and in which a relatively small amount covers a, substantial area.

Fourth, to provide a refractory vitri fled crystalline acid-type product which is very hard, resistant to very high temperatures, a good reflector of heat and. highly impervious to gass and acids.

Further objects relating to details and economies of the invention will appea i.from the description to follow. The invention. is deflned in the claims.

An embodiment of the invention in the drawing in which: p

Fig. 1 is a fragmentary view insetion of awall of a furnace, crucible or other article of refractory material, having a coating of vitrifying ingredients applied thereto, thjingredients being shown before vitrification ofgthe same to the wall and,

, Fig. 2 is a view similar to that of Eig. 1 illustrating the wall after vitrificationof ,the coating .thereto.

Referring to Fig. 1 of the drawing`| designates the wall of a furnace, fire box, cr-cihle or other article of refractory material, th "w'a having applled thereto a coating 2 of vitri f yingingredients, hereinafter named and described in detail. These ingredients are mixed in pov'v'dered form with water to the proper consisteny; preferably to that of molasses, and applied to tl e wall with ,a spray or brush, the wall being cool or only slightly warm at the time of application, otherwise blisters will form. After applyirg the coat is illustrated it is thoroughly dried in air, sunlight, a heating oven or a torch, after which the dried coating. is exposed to a temperature of 1900 F. or over for an hour or until thoroughly vitrified. I! desired, the vitrication can take place during the regular melting operation of a furnace or crucible. By applying a second coatng after the first coating has been thoroughly vitrified. the best results are obtaijnjed, as some of the first coating is absorbed by the raw bricks into the c'racks, holes and pores thereof, as shown at 3 in Fig. 1. The second coat after vitrification thereof completely seals all Weak Spots and forms a hard semi-glazed surface that resists heat and the destructive action from flames, gases and acids. Fig. 2 illustratesthe absorbed portion 3 of the coating 2, vitrified into the body of the wall I. This provides a very strong bonding connection between the wall :and the coating after vitrication of the coating. The depth of the vitrified coating beneath the surface of the wall will vary according to' the consistency of the coating and the porosity of the wall.

The coating 2 applied. to the wall I as above described, comprises the following ingredients in percentages by weight as indicated:

analysis according to thepurity and source of supply:

Zrcm'um silicate-granular, chemical composition ZrSiO4 i CZay-kaolin or china clay Asbestos-tremolite (amphibole) Chemical composition CaMg3Si40i2'" v 'j i Aluminum wide-Chemical. composition AlzOa M agnesium oxide-calcined magnesite Salt-chemical composition NaCl Micar-muscovite, chemicalicomposition H2KA13 (5104) 3 The product resulting lrom vitrification of the coating 2 containing the above ingredients is a crystallinea substance) having ahardness very close to that of diamond, equal to approximately 7 to 8 on Mohs scale. The zirconium compound being already in crystalline form is imbedded in' f.

this precipitated corundum-like formationoftthev other elements, making the whole a crystalline substance.

The remaining ingredients of the coating: 2,'

comprising sodium chloride, sodium slicate and mica, perform the functionlmore of. a binder to.

prevent the other ingredients from drawing away from the wall l during the vitrification andi the reaction resulting in the precipitated product. Afterrtheicrystalline,coating 2 is actually formed and vitried onto and intothe wall l-and cooled; no fur-ther precipitation takes place. the now finished crystallinecoating requires-;teme peratures of: 3750 to 3800 F-. This results, in a great saving in fire-brick and other refractory walis exposed to such high temperatures.

I: "Also the semi-glazed crystalline'surface-results ingifrom'the vitricationof the coating 2 as-above described; constitutes an excellent refiectorof. heat as` testst have proven that this surface; re:- fiectsheat-to: such an; extent that the brick-*furnane-wall on' the: side thereof opposite. from the coating e remains' cool during: a heating operation; Suchreection of heat` results; ini quicker heat;- u time for-a furnace, quicker; melting of; the metals and a saving in iuel. The:vit-ri ed coating will: withstandclong: periods: of reheating and is impervious to fluxes, gases and: acids common to melting furnaces and fire boxes,so destructive: to

the-brick;` 4

The `vitrcation. of the ingredients of the: coating 2 and the precipitationof, the corundum like substance havingimbedded therein; crystals of a: zirc'o'niumcompound, is not-depend'ent' upon the material of: the e wall :to which" the; coating is applied as the ingredients go through the same process' of ,Vitrfication and precipitation on flintbricl,"s`ilic'a brick, magnesite brick, set-up clays, dolomites silicon carbide, etc. The only require mentjisf that the material to be coated be able to withstand the proper vitrifying temperatures. If the coating is applied to materials that. are unable to, withstand the, proper vtrifyng: temperatures they melt down from under thevitrified coating. i

The vitried coating is adapted for' many uses but'being of 'an acid-type is particularly adapted flor useon non basic reverberatory furnacesused inmaking acid steels, on single or double-humor OH'-OVGPOLld gas fired furnaces used inmelting non-basic metals and alloys and on oil-distillate and gas fired furnaces and crucibles used in nielting brass, bronze and other non-ferrous metals and alloys, except aluminum and magr nesi m. ti

The use of the ingredients is, economical; as a. relatively small amountcovers a substantial area to 'be coated, one cpound,. whenproperly applied, covering from 6 t`o8 square. feet oi surface.

The product of the invention is. characterizecl by its resistance totemperatres up to approximately 4000? F., its hardness close to that of diamond, tsimperviousness to-gases andacids common to furnaces and cruc'ibles, its property "of reflecting heat to prevent the escape thereof through furnace and crucible walls, the economy in the use thereof, and its property of being acidtype in reaction.

I have illustrated and described my improved vitrifying composition and product in embodiments thereof which I consider practical. I have not 'attempted to illustrate and describe other embodiments or adaptations asit is believed the disclosu'e will enable those skilled in the art to embody or adapt my improvements as may be desied..

Having thus described my invention, what I claim as new and desire to secure by Letters 1".-A vitrifying composition adapted to produce a refractoryvitrified crystalline acid-type coating for refractbry" materials, comprising by weight the` following ingredients: zirconium silicate 50% to 60%, clay 10% to 20%, asbestos 7% to 15%, aluminum oxide l% to '15%, litharge 2% to- -5 magnesium oxide- 3% to 1 soda ash 2% to ,sodium chloride2%. to 8%, mica 5% to 15% and sodium silicate 1;%to, 5%, said last three named ingredients f acilitating a binding connection: of' .the oating to the refractory material.

2; Avitrifying composition adapted to produce a-refractory vitrified crystalline acid-type coating for reiractorymaterials, comprisingby' weight the following ingredentsc zirconium si1icate 50% to 60%, clay to20%, asbestos '7% to-% aluminum oxide: 4% to15%-, litharge2% to 5%, magnesium oxide 3% to 10%a carbonate 2%- to 5% selected from-the group consisting of sodium carbonate and` potassium carbonate; a chloride 2% to 8% sclectedfrom the group consistingof sodium-ehloride and potassium chloride, mica 5% to 1,5,% and a silicate 1% to 5% selected from-the groupconsisting ofsodium silicate-and potassium` silicate thelast three named ingredients facilitating a binding eonneetion of the coating to' the refractory material.

- 3. :A- -refr-actory product comprising a porous body portion: of refractory material and a refractory vitrified crystalline acidV-type coating vitried ;in the pores of said body portion` and on thesurface thereof; said refractory material* beingselected-frcm the group consisting of-re clay;: grap-hite *and-silicon' carbide, said coating being-produced by 'vitrif'ying to said body portion the'following ingredients: zirconium silicate 50%. to 60%, clay 10% to asbestos 7% to 15%, aluminum oxide 4% to 15%,^litharge 2%. to 5%, magnesum'oxide 3% to 10%, soda ash 2% to 5%, sodium chloride 2% to 8%, mica 5%: to 15% and'sodium' silieate 1% to 5%, the above perc'entagesi all being by weight, the s odium'chloride; nica and'sodium silicate acting asia binder between' the body portion and the coating' to prevent the coating from drawing away from the porous bcdy portion during the vitrification of the coating in the pores of the body portion and on the surface thereof.

4:. A reractory product comprising a porous bodyportion' of' refractory material and a: refractory Vitrified, 'crystalline acid-type coating vitrifi'edin the pores" oi said body portion and on the surface' thereof; said reractory material' being'selected from the group consisting-of 're'clay, graphite and silicon carbide, said'coating being produced by vitrifying to said body portion the following i'ngreclients: zirconium' sili'cat'e to`*`%, clay 10% to 20%, asbestos 7% to 15 aluminuin oxide 4%' to 15 litharge 2 to`=5% ma'gnesiumoxide 3% to `10%-, a carbonate 2% to selected from the group consisting of fsoiium carbonate and potassium carbonate, agch loricle 2% to 8% selected from the group consisting of sodium chloride and potassium ch1oride,`m`ca 5% to 15% and a, silicate 1% to 5% selected from the group consisting of sodium il icate and potassiun silicate, the above percent eges all being by weight, the mica, the chloride selected from thegroup consisting of sodium' chlcjride and potassum chloride, and the silicate selected from the group consisting of sodiujn silicate and potassium silicate, acting as a gbinder to prevent the coatng from drawingiawayg the porous bod y portion during the vitrification of the coating in the pores of the body po tion and on the surface thereof.

5. A ferr ry vitrified crystalline product, producedjbygitrifying the following ingredients: zirconiuhi iliate 50% to 60%,jclay to 20%, asbesto '1% `tiu-%, aluminum oxide 4% to 15 litharge'2 695%, magnesium oxide 3% to 10%, soda ash' 2%; to 5%, sodium chloride 2% to 8%, mica 5% to 15% and sodium silicate 1% to 5%, the above' percentages all being by weight.

6. A refractory vitrified crystalline product produced by vitrifying the following ingredients: zirconium silicate 50% to 60%, clay 10% to asbestos 7% to 15%, aluminum oxide 4% to 15%, litharge 2% to 5%, magnesum oxide 3% to 10%, a. carbonate' 2% to 5% selected from the group consisting of sodium carbonate and potassium carbonate, a chloride 2% to 8% selected from the group consisting of sodium chlorde and potas sium chloride, mica 5% to 15% and a silicate 1% to 5% selected from the group consisting of sodium silcate and potassum slicate, the above percentages all being by weight, said ingredients being vitrified at approximately 2090 F. and above.

7. A refractory vitrified crystalline product produced by vitrifying the following ingredients: zirconium silicate to clay 10% to 20%, asbestos 7% to 15%, aluminum oxide 4% to 15%, litharge 2% to 5%, magnesium oxide 3% to 10%, a carbonate 2% to 5% selected from the group consisting of sodium carbonate and potassium carbonate, a chloride 2% to 8% selected from the group consisting of sodium chloride and potassium chloride, mica 5% to 15% and a silicate 1% to 5% selected from the group consisting of sodium silicate and potassium silicat e, the above percentages all being by weight. i

HENRY L. WHITMAN.

REFERENCES CITED UNITED STATES PATENTS Name Date Russell Nov. 20, 1945 Number 

2. A VITRIFYING COMPOSITION ADAPATED TO PRODUCE A REFRACTORY VITRIFIED CRYSTALLINE ACID-TYPE COATING FOR REFRACTORY MATERIALS, COMPRISING BY WEIGHT THE FOLLOWING INGREDIENTS: ZIRCONIUM SILICATE 50% TO 60%, CLAY 10% TO 20%, ASBESTOS 7% TO 15%, ALUMINUM OXIDE 4% TO 15%, LITHARGE 2% TO 5%, MAGNESIUM OXIDE 3% TO 10%, A CARBONATE 2% TO 5% SELECTED FROM THE GROUP CONSISTING OF SODIUM CARBONATE AND POTASSIUM CARBONATE, A CHLORIDE 2% TO 8% SELECTED FROM THE GROUP CONSISTING OF SODIUM CHLORIDE AND POTASSIUM CHLORIDE, MICA 5% TO 15% AND A SILICATE 1% TO 5% SELECTED FROM THE GROUP CONSISTING OF SODIUM SILICATE AND POTASSIUM SILICATE, THE LAST THREE NAMED INGREDIENTS FACILITATING A BINDING CONNNECTION OF THE COATING TO THE REFRACTORY MATERIAL. 